蟾蜍灵激活低分化鼻咽癌细胞氯通道

Bufalin activates chloride channels in poorly differentiated nasopharyngeal carcinoma cells

目的:研究蟾蜍灵(bufalin)对低分化鼻咽癌(CNE-2Z)细胞氯通道的激活作用以及通道的特性。方法:采用全细胞膜片钳技术记录蟾蜍灵激活CNE-2Z细胞膜电流并分析其电流特征。结果:细胞外灌流1μmol/L的蟾蜍灵可诱发CNE-2Z细胞产生一个氯电流,该电流潜伏期较长,为(12.1±6.4)min,其翻转电位接近氯离子平衡电位。该电流具有较明显的外向优势,没有明显的时间依赖性失活和电压依赖性失活。氯通道阻断剂他莫昔芬(tamoxifen)可完全抑制该电流,细胞外灌流高渗液也可完全抑制该电流。结论:蟾蜍灵可以激活CNE-2Z细胞氯通道产生氯电流,与容积激活性氯电流相比,该电流的潜伏期较长,并且有更明显的外向优势。

AIM：To investigate the activation of chloride channels induced by bufalin and the properties of the channels in poorly differentiated nasopharyngeal carcinoma（CNE-2Z）cells.METHODS：The technique of whole-cell patch clamp was used to record the chloride currents and to analyze the characteristics of the currents in CNE-2Z cells. RESULTS：A chloride current was slowly activated by extracellular application of bufalin（1μmol/L）.The activation of the current was slower than that of the volume-activated chloride current,with an activation latency of（12.1±6.4）min. The reversal potential of the current was close to the calculated Cl^-equilibrium potential（E_（Cl）=-0.9 mV）.The chloride current was outward-rectified and did not show significant time-dependent or voltage-dependent inactivation.The chloride channel blocker tamoxifen completely inhibited the outward and inward currents.The current was also completely inhibited by extra-cellular application of 47%hypertonic solution.CONCLUSION：Bufalin activates chloride channels and induces a chloride current in CNE-2Z cells.Compared with the volume-activated chloride current in CNE-2Z cells,the activation latency of the bufalin-induced current is longer and the outward rectification is more obvious.